Now, researchers are using biomaterials and food with 3D printers, and the objects made using more traditional materials are becoming more complicated every day. Here are 10 intriguing items in development or currently being made with 3D printers.

Contour Crafting, a technology NASA's eyeing for off-planet housing, is a robotic extruding method. Like smaller 3D printers, the “printer” head follows designs from CAD software. The printer uses cement or a plaster/polymer mix, and designs can be customized while work is underway.

The machines can also automatically embed electrical, plumbing and air-conditioning conduits, and place electronic sensors to monitor a building's temperature and health, says Behrokh Khoshnevis, professor of industrial and systems engineering at USC's Viterbi School of Engineering.

Khoshnevis, who is leading the effort to perfect Contour Crafting construction, believes 3D printed buildings will address the problem of population growth; the technology -- which Khoshnevis expects to be commercially viable within two years -- could finish a house's shell in a day.

One of the inspirations behind the development of 3D printers was the desire to create self-replicating machines. An obstacle to this was a lack of suitable materials to produce electronics.

Enter the Cartesian Co., the Australia-based creator of the Argentum printer. The machine sprays out conductive inks (made of silver nano particles) onto paper, fabrics, acrylic, plastics, MDF, FR4 and other fiberglass substrates. That means the circuit boards can be flexible or even worn on clothing. A 2-in. × 2-in. board can be printed in 10-20 minutes, depending on the level of circuitry.

The project's Kickstarter effort exceeded its $30,000 goal by $107,000. When available in September, the Argentum 3D printer will retail for $1,599.

Image courtesy Natural Machines. This pizza was printed raw by Natural Machines 3D printing technology. It was then cooked.

3D printed food

Last year, Abraham Reichental, CEO of 3D Systems, said that a 3D printer capable of making food will some day sit on every counter. Six months later, 3D Systems is selling the ChefJet, a 3D printer that can print confections ranging from cake toppings to chocolate.

It's not alone in the charge toward consumerization of 3D printed food. Barcelona-based Natural Machines started out printing chocolates but has upgraded to ravioli, cheeseburgers and pizza. Food cartridges hold premixed ingredients (3.3 ounces each) and an extruder nozzle lays the ingredients on a plate for cooking.

“It’s not the Star Trek replicator yet. It also doesn’t cook the food,” said Lynette Kucsma, co-founder of the company. “It’s more an assembly device, but the food is pretty true to life.”

Image courtesy Natural Machines. With the exception of the lettuce and tomato, this cheeseburger and bun were the creation of Natural Machines' 3D printer.

The future of 3D printed food

A promising 3D printed food project is in development at Intellectual Ventures Laboratory in Bellevue, Wash. There, researchers are creating ink cartridges filled with freeze dried, pulverized food to someday send to third world nations where, by adding water, it could be printed and cooked at the extruder nozzle.

The 3D printer would dispense a pixel of food at a time, hydrate it with a needle, cook it with a laser and repeat the process until an entire meal is complete.

Additionally, because food is precisely measured, researchers could track nutritional data and a person's health over time. The project is in the early stages; while foods such as smoothies and Cliff Bars have been made, complex meals have yet to materialize.

Bio-printing lays down multiple layers of live cells to form human tissue. The biggest obstacle is manufacturing the vascular system needed to provide life-sustaining oxygen and nutrients.

Organovo said it's overcome that vascular issue, to a degree. It achieved thicknesses of over 500 microns and maintained liver tissue in a fully functional state for at least 40 days.

It'll take a decade or more to perfect the technology, but someday 3D bioprinting could recreate organs for transplants using patients' own cells. Today, pharmaceutical testing is beginning to use 3D printed tissue to create more targeted medications.

Image courtesy University of Glasgow. The Chemputer is made up of two standard 3D printers adapted for manufacturing test tubes and laying down a set of universal chemical ink in order to create pharmaceuticals on the fly.

3D printed pharmaceuticals

University of Glasgow researchers are adapting 3D printing technology to create downloadable pharmaceuticals. Calling it a “Chemputer,” they used two commercial, $2000 3D printers to assemble chemical compounds using open-source CAD software. One 3D printer makes the beakers and the other the chemical molecules. Combined, the researchers call them Reactionware vessels.

Professor Lee Cronin, who leads the research team, said the technology could create drugs in a new way using a universal set of chemical inks. "You download the blueprint -- the organic chemistry -- for that molecule and make it in the device. You can make your molecule in the printer using this software," he said during a TED talk. "Ultimately, it could mean you can print your own medicine."

The research, published in the peer-reviewed journal Nature, demonstrated how printing a vessel with “catalyst-laced ink,” together with another container with built-in carbon-based electrodes, stimulated an electrochemical reaction within the vessel.

The printers have synthesized previously unreported compounds, according to the researchers. While still in the early stages, Cronin sees a day when consumers could download and print personalized medications.

“Perhaps with the introduction of carefully-controlled software ‘apps,’ we could see consumers have access to a personal drug designer they could use at home to create the medication they need,” he said in a statement.

Image courtesy Lucas Mearian. Leon McCarthy, 12, shows off his hand, which was made on a 3D printer for about $5 in materials.

3D printed prosthetics

If 3D printing could only claim one popular victory, it would likely be the ability to make affordable prosthetics. Case in point, Leon McCarthy. McCarthy is a 12-year-old with no left hand whose father worked with an online prosthetics development community to 3D print a working hand for $5.

Leon’s father worked with others on e-NABLE, a Google Plus prosthetics development community, to design the hand. The hand's various parts were then printed on a machine owned by a local middle school.

3D printed prosthetics have also given hope to amputees in war-torn regions throughout the world, including Sudan. There, a non-profit initiative called Project Daniel has brought in 3D printers, laptops and spools of plastic filament to try to meet the needs in a nation with more than 50,000 amputees.

The project was started by Mick Ebeling, founder of Not Impossible Labs, who was moved by the story of Daniel Omar. Omar was 14 when his arms were blown off by a bomb. For about $350 in materials, a prosthetic arm was built for Daniel, and for the first time since losing his arms, he was able to feed himself. Now locals are making their own prosthetics using 3D printers.

Image courtesy Kor Ecologic Inc. Image of the Urbee, a hybrid car that began as a Kickstarter project, recharges via solar power. The cars developers claim the 3D printed body is the most aerodynamic ever made.

3D printed cars

Because 3D printing offers more than 100 material types – including thermoplastics, metals, and ceramics -- automobile manufacturers, the aerospace industry and the military have all taken to using the rapid prototyping to design vehicles and parts. Today, all major auto manufacturers use 3D printing in rapid prototyping automobiles and their parts because it’s vastly faster, simpler and less expensive than traditional methods using modeling clay.

Urbee, a hybrid car that began as a Kickstarter project and recharges via solar power, has a 3D printed body so aerodynamic that it has a coefficient of drag of just .15 and can reach speeds of 68 mph.

MIT and 3D printer maker Stratasys are collaborating to produce 3D printed objects that can automatically come together to create a larger object.

The technology, coined “4D Printing,” creates objects of varying shapes able to transform by connecting to other 3D printed objects. Created at the MIT Self-Assembly Lab, the “smart” or programmable materials have a form of memory and use passive energy such as heat, gravity, movement or pneumatics to reconfigure over time; imagine a series of tubes or balls that connect to form new shapes, such as boxes or hexagons.

The technology could replace some forms of industrial manufacturing assembly. “We’re trying to give a voice to materials to collaborate with people,” says Skylar Tibbits, director of MIT's Self Assembly Lab.

The batteries are actually interlaced stacks of tiny battery electrodes. To create the microbattery, the custom-built 3D printers extrude conductive inks through a nozzle that's about 30 microns in diameter.

The researchers see the microbatteries as a possible source of electricity for tiny devices that could be used in areas ranging from miniaturized medical implants to micro-communications.

Leading 3D printing companies, such as Stratasys and 3D Systems, have already proven their technology could turn the fashion world on its head by allowing artists to design their clothing in a virtual world before printing them out, sans sewing machine.

3D Printed dresses using Stratasys’ Objet Connex500 multi-material 3D printer even graced the catwalk at Paris Fashion Week last year. 3D printed shoes, hats and accessories, such as jewelry, are also common place these days in the world of additive manufacturing.